Spelunker is a 1983 video game developed by Tim Martin and MicroGraphicImage. It is a platform game similar to Pitfall! or Curse of Ra. Originally released by MicroGraphicImage for the Atari 8-bit computers in 1983, the game was later ported to the Commodore 64 and re-released by Brøderbund in 1984, with European publishing rights licensed to Ariolasoft. An arcade version followed in 1985, and the game was released for the NES on December 6, 1985 in Japan and September, 1987 in North America, and for the MSX in 1986.
Spelunker is set in a colossal cave, with the player starting at the cave's entrance at the top, and the objective is to get to the fabulous treasure at the bottom. To achieve this, the player must walk and jump through increasingly challenging parts of the cave, all the while working with a finite supply of fresh air, which could be replenished at various points.
Some of the hazards the player faces in the cave include water, uneven terrain, steam vents, small ledges, chasms, deadly pits, and large rocks that must be blown away. One of the few enemies are large bats, which drop deadly guano on the player. Additionally, a ghost haunts the cave, appearing randomly and attempting to take the player to the shadow world. By pressing the spacebar (B button for NES version), the player character sends a blast of air from his airtank (uses a Phantom Blaster in the NES version), pushing the ghost away. However, this renders the player's character immobile for a couple of seconds, thus vulnerable to other dangers and further depleting their air supply.
Objects to collect include sticks of dynamite, flares and keys (which come in two different colours). By pressing the 'D' key, a stick of dynamite is dropped and ignited. This can be used to blow away big rocks. (Care must be taken to stand far enough away as not to get caught in the blast.) Flares are launched with the 'F' key and are used to scare bats away. After the flare is extinguished, the bats return.
Much of the game's difficulty arises from the fact that the explorer cannot jump high or fall far, and therefore dies easily. There is also no projectile motion when running off the edge of a cliff so the character will fall straight down. As such, precise positioning and jumping play key factors in successfully completing the game. Additionally, certain versions of the game are very precise about jumping from ropes or ladders. The NES and MSX versions require the player to move sideways before pressing the jump button (risking walking off the ladder or rope). The Atari version and the Commodore version allowed the player to hold the button and tap the joystick instead to make a single jump from a ladder or rope from a standstill.
The splash screen of the game on the original Atari featured an excerpt of Modest Mussorgsky's Pictures at an Exhibition as background music. All other versions of the game, including the Atari re-release featured a different title theme. The NES and MSX versions had additional music during gameplay.